The invention relates generally to grinding wheels and more particularly to an improved super abrasive grinding wheel having titanium aluminum nitride and hard lubricant coatings.
The performance of grinding wheels is a slowly but constantly evolving technology. Because of the pervasive use of grinding in numerous manufacturing processes, there has been a constant incentive to increase grinding wheel performance the primary criteria of which is enhanced service life. A significant increase in service life over conventional aluminum oxide grinding wheels was achieved by the incorporation of the first super abrasive, diamond, as diamond fragments or particles into the grinding wheel or on the peripheral surface of the grinding wheel. Grinding wheels utilizing diamond, however, were not successfully used with steels and other ferrous alloys because of the tendency of diamond to react with and be absorbed into such materials at the temperatures and pressures existing at the grinding wheel/material interface. This shortcoming has significantly reduced the utilization of such grinding wheels when grinding ferrous materials.
More recently, a manmade super abrasive, cubic boron nitride (cBN), has not only provided improved service life but also functioned with a wider variety of materials, particularly steels, hardened steels, stainless steels, and nickel and cobalt based super alloys. Cubic boron nitride grinding wheels typically perform better than diamond materials with steel and other ferrous alloys.
Cubic boron nitride grinding wheels typically comprise a metal wheel or core with a periphery onto which the cubic boron nitride particles or fragments are secured by electroplating, electroless plating or brazing.
U.S. Pat. No. 5,139,537 discloses the coating of such grinding wheels with titanium nitride. Such a coating is said to greatly strengthen the adherence of the cBN particles to the grinding wheel.
As noted above, however, due to the evolutionary improvements in grinding wheel technology, further performance enhancements are anticipated and the present invention as directed to a grinding wheel having improved performance characteristics.
A grinding wheel according to the present invention includes cubic boron nitride (cBN) or other abrasive particles such as diamond secured to a substrate by an electroplated, electroless plated or brazed layer of nickel, chrome or nickel or chrome based alloy, a first antioxidation layer of, for example, vapor deposited titanium aluminum nitride (TiAIN) and a second hard lubricant layer of, for example, vapor deposited molybdenum disulfide (MoS2), diamond graphite, tungsten carbide carbon, carbon nitride, titanium carbide carbon or titanium carbon nitride. The hard lubricant layer acts as a release agent and lubricant which reduces clogging of the wheel by lowering adhesion and facilitating the release of ground material from the wheel thereby providing improved grinding performance.
Thus it is an object of the present invention to provide a grinding wheel having grinding media coated with a first antioxidation layer and a second hard lubricant layer.
It is a further object of the present invention to provide a grinding wheel having grinding media covered with a first layer of vapor deposited titanium aluminum nitride and a second layer of a vapor deposited hard lubricant such as molybdenum disulfide, diamond graphite, tungsten carbide carbon, carbon nitride, titanium carbide carbon or titanium carbon nitride.
It is a still further object of the present invention to provide a grinding wheel having cubic boron nitride abrasive particles coated by layers of titanium aluminum nitride and molybdenum disulfide, diamond graphite, tungsten carbide carbon, carbon nitride, titanium carbide carbon or titanium carbon nitride.
It is a still further object of the present invention to provide a grinding wheel having electroplated, electroless plated or brazed nickel, chrome or nickel or chrome based alloys securing cubic boron nitride abrasive particles which are coated by a first antioxidizing layer of titanium aluminum nitride and a second hard lubricant layer of molybdenum disulfide, diamond graphite or tungsten carbide carbon, carbon nitride, titanium carbide carbon or titanium carbon nitride.
Further objects and advantages of the present invention will become apparent by reference to the following description and appended drawings wherein like reference numbers refer to the same component, element or feature.